A single-end protection method for UHV DC transmission lines

A technology for UHV DC and transmission lines, applied to emergency protection circuit devices, electrical components, etc., can solve the problems of slow protection action, easy refusal, and low sensitivity of current differential protection, so as to ensure quick action and good speed Dynamic, to achieve the effect of full-line protection

Active Publication Date: 2017-10-27
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traveling wave protection and differential undervoltage protection tend to refuse to operate in case of high-impedance grounding fault, current differential protection has low sensitivity and slow protection action
[0003] Transient protection using boundary to high-frequency attenuation characteristics is the development direction of UHV DC transmission line protection. In recent years, scholars have studied transient protection using boundary to high-frequency quantity attenuation characteristics as a UHV DC transmission line protection method. Usually, the attenuation characteristics of UHV DC ultra-long transmission lines are not considered, so full-line protection in the true sense cannot be realized

Method used

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  • A single-end protection method for UHV DC transmission lines
  • A single-end protection method for UHV DC transmission lines
  • A single-end protection method for UHV DC transmission lines

Examples

Experimental program
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Effect test

Embodiment 1

[0035] Embodiment 1: as Figure 1-2 As shown in the figure, a single-ended protection method for UHV DC transmission lines, firstly use the data acquisition device to collect the fault current data in the time window 5 ms after the arrival of the first wave of the fault current traveling wave and calculate the 1-mode component; then the 1-mode component Subtract the 1-mode current in normal operation before the fault from the current signal to obtain the fault current variation and sum it, and then judge whether the signal comes from outside the rectifier side area or from the line or inverter side area according to the summation result; For the fault current signal from the line or outside the inverter side area, use the Hilbert-Huang transformation to obtain the maximum value of the instantaneous frequency, and then compare the maximum value of the instantaneous frequency with the preset threshold value to judge the fault Occurs on the line or outside the inverter side area....

Embodiment 2

[0045] Embodiment 2: as Figure 1-2 As shown in the figure, a single-ended protection method for UHV DC transmission lines, firstly use the data acquisition device to collect the fault current data in the time window 5 ms after the arrival of the first wave of the fault current traveling wave and calculate the 1-mode component; then the 1-mode component Subtract the 1-mode current in normal operation before the fault from the current signal to obtain the fault current variation and sum it, and then judge whether the signal comes from outside the rectifier side area or from the line or inverter side area according to the summation result; For the fault current signal from the line or outside the inverter side area, use the Hilbert-Huang transformation to obtain the maximum value of the instantaneous frequency, and then compare the maximum value of the instantaneous frequency with the preset threshold value to judge the fault Occurs on the line or outside the inverter side area....

Embodiment 3

[0054] Embodiment 3: as Figure 1-2 As shown, a single-end protection method for UHV DC transmission lines, the specific steps of the method are as follows: a ground fault occurs on the positive busbar at the rectification side, and the transition resistance is 1 ohm. Collect the current on the two-pole lines in the window 5ms after the arrival of the first wave head of the fault traveling wave, and obtain the 1-mode component of the current; obtain the fault current variation Δi (where, in this example, i normal It is the value when the system is in full load and normal operation, the value is 6.25kA), and then use the formula to get the P value -148.8482, which is judged to be an out-of-area fault on the rectifier side, and the protection does not operate.

[0055] Because the sampling rate in the present invention is 10kHz, and the sampling time window is 5ms, the K value used is 50, which is the same in the following examples.

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Abstract

The invention relates to a single-end protection method for an ultra-high voltage direct current transmission line, belonging to the technical field of relay protection for a high voltage direct current transmission system. The present invention first utilizes the data acquisition device to collect the fault current data in the time window 5 ms after the head of the fault current traveling wave arrives and obtains the 1-mode component; then subtracts the 1-mode current signal during normal operation before the fault from the 1-mode component current signal , to obtain the fault current variation and perform a summation operation, and then judge whether the signal is from outside the rectifier side area or from outside the line or inverter side area according to the summation result; for the fault current signal from outside the line or inverter side area Use the Hilbert-Huang transform to obtain the maximum value of the instantaneous frequency, and then compare the maximum value of the instantaneous frequency with the preset threshold value to judge whether the fault occurs on the line or outside the inverter side area. The invention can realize full-line protection of UHV direct current transmission lines, and can ensure good quick movement.

Description

technical field [0001] The invention relates to a single-end protection method for an ultra-high voltage direct current transmission line, belonging to the technical field of relay protection for high voltage direct current transmission systems. Background technique [0002] Currently, traveling wave protection is the main protection in DC line protection, with differential undervoltage protection and differential protection as backup protection. Traveling wave protection and differential undervoltage protection tend to refuse to operate when there is a high-impedance ground fault, and the sensitivity of current differential protection is not high, and the protection action is slow. [0003] Transient protection using boundary to high-frequency attenuation characteristics is the development direction of UHV DC transmission line protection. In recent years, scholars have studied transient protection using boundary to high-frequency quantity attenuation characteristics as UHV ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/26
Inventor 陈仕龙张杰毕贵红谢佳伟李兴旺荣俊香曹蕊蕊
Owner KUNMING UNIV OF SCI & TECH
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